1. Field of the Invention
The invention is concerned with the field of code-detection and relates to a device, which is composed of a transmitter, a receiver and a code carrier, the transmission medium preferably being light and, thus, the receiver being a light sensitive element.
The scanning of code carriers, which can be recording tracks for magnetic scanning, arrangements of colors for light-scanning, charge patterns for electrical scanning etc., are substantially based on the principle of scanning in series (serial scanning). This requires that either the scanning means is in movement or that the code carrier is in movement. This requires a movement between the code arrangement in relation to the means detecting this code arrangement. In general the code carrier is directed past the reading device or detecting device, because scanning devices are very expensive.
The guiding of the carrier has to satisfy high requirements in order to obtain a reasonable detection. This has the direct effect of an increase of the mechanical expense. Inaccuracies in the guiding of the code carrier deteriorate the security of identification. That means that the entire coding becomes questionable, if this security is not guaranteed. Furthermore apart from the exact guiding and moving of the carriers other mechanisms are necessary, which register and control the process of the movement. As is known, this is realized by means of synchronization marks on a synchronization track, which are provided additionally and which ar connected closely to the coding. This supplementary expense does not render the process of reading and scanning any easier, but on the contrary, taking into account the disposal of other geometrical provided elements, the requirements of the system augment.